Micromechanical properties of polymeric coatings

In earlier studies, PTFE-based coatings showed superb tribological performance under aggressive conditions, relevant to air-conditioning and refrigeration compressors. In this work, micromechanical properties of different polymeric coatings (PTFE-, PEEK-, resin- and fluorocarbon-based coatings) coated on gray cast iron, were examined using instrumented microindentation. The load–unload responses were used to measure the load-bearing properties of the coatings, as well as to extract their elastic modulus and hardness values. Induced structural differences between the PTFE- and PEEK-based coatings were confirmed using scanning electron microscopy. These measurements were used to explain the difference in the tribological performance between PTFE- and PEEK-based coatings. Such correlation is useful as simpler indentation experiments could be readily performed, compared to more complex and application-specific tribological experiments.